磁暴期间环电流离子中性原子成像的模拟与观测比较研究

采用已经建立的环电流离子解析模型,结合Chamberlain地冕中性层模型,研究了2004年11月一次大磁暴期间的环电流区域中性原子(ENA)图像.结果表明,模拟的ENA图像与TC-2卫星搭载的中性原子成像仪(NUAUD)的观测图像在方位角或地方时分布、高度或纬度分布和能谱分布方面存在一定的差异.如果依据磁暴发展的不同阶段来选择环电流离子模型的方位角不对称因子和通量最大方向的方位角,增大地冕中性层在低高度区域的密度或者考虑氢(H)以外的其他中性成分,改进注入边界处的离子能谱分布函数,且考虑不同种类环电流离子的比例随磁暴发展可能发生的变化,该模型有望产生更符合观测的模拟ENA图像.

Energetic Neutral Atom Imaging of the Earth Ring Current During Magnetic Storms Comparison Between Simulation Results and Observation

Based on an analytical ion model for the ring current,in conjunction with the Chamberlain exosphere density model,Energetic Neutral Atom(ENA) images were calculated for the magnetic storm occurred in November 2004.It was shown that the simulated ENA images differ from images recorded by the Energetic Neutral Atom Detector Unit(NUADU) instrument aboard TC-2 of Double Star mission in terms of azimuth/magnetic Local Time(MLT) distribution,altitude /latitude distribution and energy spectral distribution.If the determiner of asymmetry of the ring current and azimuth of flux maximum can be selected according to evolvement of storms,and more emphasis be placed on density of low altitude exosphere or neutral atoms other than H be taken into account,the ion model is hopeful to produce more precise ring current ion distributions and ENA images.In addition,the ion spectrum at the injection region is expected to be revised and change of ratio of different ion species should be taken into account in order to get better simulation results.